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From 82eda2c33b5d4ac34e36e020ba2c86df91861381 Mon Sep 17 00:00:00 2001
Message-Id: <82eda2c33b5d4ac34e36e020ba2c86df91861381.1601675152.git.zanussi@kernel.org>
In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Fri, 21 Feb 2014 17:24:04 +0100
Subject: [PATCH 221/333] crypto: Reduce preempt disabled regions, more algos
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
Don Estabrook reported
| kernel: WARNING: CPU: 2 PID: 858 at kernel/sched/core.c:2428 migrate_disable+0xed/0x100()
| kernel: WARNING: CPU: 2 PID: 858 at kernel/sched/core.c:2462 migrate_enable+0x17b/0x200()
| kernel: WARNING: CPU: 3 PID: 865 at kernel/sched/core.c:2428 migrate_disable+0xed/0x100()
and his backtrace showed some crypto functions which looked fine.
The problem is the following sequence:
glue_xts_crypt_128bit()
{
blkcipher_walk_virt(); /* normal migrate_disable() */
glue_fpu_begin(); /* get atomic */
while (nbytes) {
__glue_xts_crypt_128bit();
blkcipher_walk_done(); /* with nbytes = 0, migrate_enable()
* while we are atomic */
};
glue_fpu_end() /* no longer atomic */
}
and this is why the counter get out of sync and the warning is printed.
The other problem is that we are non-preemptible between
glue_fpu_begin() and glue_fpu_end() and the latency grows. To fix this,
I shorten the FPU off region and ensure blkcipher_walk_done() is called
with preemption enabled. This might hurt the performance because we now
enable/disable the FPU state more often but we gain lower latency and
the bug is gone.
Reported-by: Don Estabrook <don.estabrook@gmail.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
arch/x86/crypto/cast5_avx_glue.c | 21 +++++++++------------
arch/x86/crypto/glue_helper.c | 31 ++++++++++++++++---------------
2 files changed, 25 insertions(+), 27 deletions(-)
diff --git a/arch/x86/crypto/cast5_avx_glue.c b/arch/x86/crypto/cast5_avx_glue.c
index 41034745d6a2..d4bf7fc02ee7 100644
--- a/arch/x86/crypto/cast5_avx_glue.c
+++ b/arch/x86/crypto/cast5_avx_glue.c
@@ -61,7 +61,7 @@ static inline void cast5_fpu_end(bool fpu_enabled)
static int ecb_crypt(struct skcipher_request *req, bool enc)
{
- bool fpu_enabled = false;
+ bool fpu_enabled;
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
struct skcipher_walk walk;
@@ -76,7 +76,7 @@ static int ecb_crypt(struct skcipher_request *req, bool enc)
u8 *wsrc = walk.src.virt.addr;
u8 *wdst = walk.dst.virt.addr;
- fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+ fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
/* Process multi-block batch */
if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
@@ -105,10 +105,9 @@ static int ecb_crypt(struct skcipher_request *req, bool enc)
} while (nbytes >= bsize);
done:
+ cast5_fpu_end(fpu_enabled);
err = skcipher_walk_done(&walk, nbytes);
}
-
- cast5_fpu_end(fpu_enabled);
return err;
}
@@ -212,7 +211,7 @@ static int cbc_decrypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
- bool fpu_enabled = false;
+ bool fpu_enabled;
struct skcipher_walk walk;
unsigned int nbytes;
int err;
@@ -220,12 +219,11 @@ static int cbc_decrypt(struct skcipher_request *req)
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes)) {
- fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+ fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
nbytes = __cbc_decrypt(ctx, &walk);
+ cast5_fpu_end(fpu_enabled);
err = skcipher_walk_done(&walk, nbytes);
}
-
- cast5_fpu_end(fpu_enabled);
return err;
}
@@ -292,7 +290,7 @@ static int ctr_crypt(struct skcipher_request *req)
{
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
- bool fpu_enabled = false;
+ bool fpu_enabled;
struct skcipher_walk walk;
unsigned int nbytes;
int err;
@@ -300,13 +298,12 @@ static int ctr_crypt(struct skcipher_request *req)
err = skcipher_walk_virt(&walk, req, false);
while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {
- fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+ fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
nbytes = __ctr_crypt(&walk, ctx);
+ cast5_fpu_end(fpu_enabled);
err = skcipher_walk_done(&walk, nbytes);
}
- cast5_fpu_end(fpu_enabled);
-
if (walk.nbytes) {
ctr_crypt_final(&walk, ctx);
err = skcipher_walk_done(&walk, 0);
diff --git a/arch/x86/crypto/glue_helper.c b/arch/x86/crypto/glue_helper.c
index a78ef99a9981..dac489a1c4da 100644
--- a/arch/x86/crypto/glue_helper.c
+++ b/arch/x86/crypto/glue_helper.c
@@ -38,7 +38,7 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
- bool fpu_enabled = false;
+ bool fpu_enabled;
unsigned int nbytes;
int err;
@@ -51,7 +51,7 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
unsigned int i;
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
- &walk, fpu_enabled, nbytes);
+ &walk, false, nbytes);
for (i = 0; i < gctx->num_funcs; i++) {
func_bytes = bsize * gctx->funcs[i].num_blocks;
@@ -69,10 +69,9 @@ int glue_ecb_req_128bit(const struct common_glue_ctx *gctx,
if (nbytes < bsize)
break;
}
+ glue_fpu_end(fpu_enabled);
err = skcipher_walk_done(&walk, nbytes);
}
-
- glue_fpu_end(fpu_enabled);
return err;
}
EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);
@@ -115,7 +114,7 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
- bool fpu_enabled = false;
+ bool fpu_enabled;
unsigned int nbytes;
int err;
@@ -129,7 +128,7 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
u128 last_iv;
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
- &walk, fpu_enabled, nbytes);
+ &walk, false, nbytes);
/* Start of the last block. */
src += nbytes / bsize - 1;
dst += nbytes / bsize - 1;
@@ -161,10 +160,10 @@ int glue_cbc_decrypt_req_128bit(const struct common_glue_ctx *gctx,
done:
u128_xor(dst, dst, (u128 *)walk.iv);
*(u128 *)walk.iv = last_iv;
+ glue_fpu_end(fpu_enabled);
err = skcipher_walk_done(&walk, nbytes);
}
- glue_fpu_end(fpu_enabled);
return err;
}
EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
@@ -175,7 +174,7 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
- bool fpu_enabled = false;
+ bool fpu_enabled;
unsigned int nbytes;
int err;
@@ -189,7 +188,7 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
le128 ctrblk;
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
- &walk, fpu_enabled, nbytes);
+ &walk, false, nbytes);
be128_to_le128(&ctrblk, (be128 *)walk.iv);
@@ -213,11 +212,10 @@ int glue_ctr_req_128bit(const struct common_glue_ctx *gctx,
}
le128_to_be128((be128 *)walk.iv, &ctrblk);
+ glue_fpu_end(fpu_enabled);
err = skcipher_walk_done(&walk, nbytes);
}
- glue_fpu_end(fpu_enabled);
-
if (nbytes) {
le128 ctrblk;
u128 tmp;
@@ -278,7 +276,7 @@ int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
{
const unsigned int bsize = 128 / 8;
struct skcipher_walk walk;
- bool fpu_enabled = false;
+ bool fpu_enabled;
unsigned int nbytes;
int err;
@@ -289,21 +287,24 @@ int glue_xts_req_128bit(const struct common_glue_ctx *gctx,
/* set minimum length to bsize, for tweak_fn */
fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
- &walk, fpu_enabled,
+ &walk, false,
nbytes < bsize ? bsize : nbytes);
/* calculate first value of T */
tweak_fn(tweak_ctx, walk.iv, walk.iv);
while (nbytes) {
+ fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+ &walk, fpu_enabled,
+ nbytes < bsize ? bsize : nbytes);
nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
+ glue_fpu_end(fpu_enabled);
+ fpu_enabled = false;
err = skcipher_walk_done(&walk, nbytes);
nbytes = walk.nbytes;
}
- glue_fpu_end(fpu_enabled);
-
return err;
}
EXPORT_SYMBOL_GPL(glue_xts_req_128bit);
--
2.17.1
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